1. Summarize sociocultural factors that can foster differences in racial and ethnic caregiving burdens 2. Summarize knowledge about disparities in racial and ethnic groups' risk of different types of caregiving burdens Family caregivers are integral to cancer patients' care and often experience significant burdens. Considerable research has demonstrated that Black and Hispanic cancer patients experience worse healthcare delivery and health outcomes compared to Whites, yet less is known about how caregiving burdens may differ by racial or ethnic group in cancer care. We analyzed cross-sectional data from the Cancer Care Outcomes Research and Surveillance Consortium, a large multiregional population-based study of individuals with colorectal or lung cancers and their caregivers. Bivariate and multivariate regression models assessed differences by racial/ethnic group (non-Hispanic Black, Hispanic, and non-Hispanic White) in caregiving responsibilities and burden in three domains: social/emotional, financial, and health. We used structural equation modeling to examine whether sociocultural factors (social support, caregiving preparedness, and caregiver-patient communication) mediated racial/ethnic differences in caregiving burden type. In unadjusted models, compared with non-Hispanic White caregivers (N = 1,169), Black (N = 220) and Hispanic (N = 84) caregivers spent more time caregiving (18 vs. 26 vs. 26 hours/week; P < 0.001), completed more tasks (6.8 vs. 7.6 vs. 8.7; P < 0.05), and reported greater financial burden (P < 0.02). Yet, compared to non-Hispanic Whites, Black caregivers reported lower social/emotional (P < 0.01) and health burdens (P < 0.01), and Hispanic caregivers reported similar burden levels. In structural equation models, caregivers' social support and caregiving preparedness partially mediated the Black-White gap for all three burden types. None of the factors examined mediated the Hispanic-White gap in burdens. Black and Hispanic caregivers perform more caregiving tasks and report greater financial burden than non-Hispanic Whites but experience lower or equivalent social/emotional and health burdens. Black-White burden differences are partially explained by race-based differences in caregivers' social support and caregiving preparedness. Interventions that build social support and caregiving preparedness may reduce caregiving burden across all racial/ethnic groups. [ABSTRACT FROM AUTHOR]